1. Make crust: In a large bowl, whisk together flour, salt, and sugar.
Using a pastry cutter, add shortening and chilled butter and cut into flour mixture
until it resembles coarse crumbs. (Some will look like oatmeal flakes,
others will be the size of peas.) Stir together ice water and vinegar.
Make a well in the center of the flour mixture, and add liquid, stirring
until dough comes together and holds together when squeezed.
If mixture is too dry, add additional water, a teaspoon at a time, until
it reaches the right consistency.
2. Divide dough in half and create a disk out of each. Wrap each disk in
plastic wrap and refrigerate until cold, at least 1 hour.
3. Make filling: Chop peaches into small pieces (about ½-inch dice). Mix
in a medium bowl with sugar, flour, cornstarch, and spices. Add bourbon
(if using) and vanilla extract, stirring to combine.
4. Assemble: Preheat oven to 375F. Line baking sheets with parchment
paper; set aside. On a lightly floured surface, roll one dough disk out
to 1/8-inch thick. Cut out circles with a 3-inch cutter, gathering
scraps and rerolling. (If dough becomes soft, chill in refrigerator
again.) Repeat with remaining dough.
5. Spoon about 2 teaspoons of filling into the center of each circle,
making sure not to overfill (otherwise it won’t seal!) and brush the
edges of the circle with a bit of egg wash. Fold dough over to create a
half circle, and press the edges firmly with the tines of a fork to
seal. Place on prepared baking sheets. Repeat with remaining dough
rounds. Chill on baking sheets for another 30 minutes.
6. In a small bowl, mix together granulated sugar and cinnamon for the
topping. Remove chilled pies from oven and cut a small slit in the top
of each. Lightly brush the tops with egg wash and sprinkle with sugar
mixture. Bake, rotating pans halfway through, until tops are golden
brown, about 16 to 18 minutes. Remove from the oven and let cool
slightly before serving.